As the development of optical scanning systems and video transmission systems has continued to improve, the use of such systems for remote tele-monitoring and for control purposes, such as in remotely piloted vehicles (e.g. reconnaissance and weapon delivery aircraft) has become particularly attractive. In the course of operation of such systems an operator, usually ground based, communicates with and may actually control the flight of the remote vechicle via a control/display console which is coupled with camera and guidance control equipment on the remote vehicle by means of a radio communication link. A general illustration of such a system is shown in FIG. 1, wherein an operator 10 at a control/display console 40 observes on the face of a display 50 (e.g. a CRT display) a scene 30 as viewed by camera equipment carried by a remotely piloted vehicle 20, signals representative of the scene having been transmitted over an imagery communication link to the ground station. The control console 40 normally permits the operator to return guidance and camera-pointing commands to the remotely piloted vehicle 20. The function of the operator may typically require him to maneuver the remotely piloted vehicle and/or slew the camera equipment so as to observe navigation landmarks over which the remotely piloted vehicle flies. Upon approaching a remote target area, the aircraft and/or the camera are maneuvered so as to permit the viewing optics clearly observe the target; the returned video data is recorded and subsequently transferred to a permanent hard copy photograph of the scene for detailed analysis. Since it is normally required that the image returned to the command console be of a fairly high quality, particularly in the case of a reconnaissance flight, the data link bandwidth for effecting the required transmission of video information can be very high.
In an effort to reduce this bandwidth, there have been proposed imaging/transmission systems whereby only a delimited portion of the scene being displayed to the console operator contains a high resolution image. The premise upon which such systems operate is the fact that the portion of a scene observed by an individual at any instant contains much more information than the observer can use. Using this underlying principle, such systems control the action of the camera equipment upon the remote vehicle so as to effectively reduce its field of view or so as to confine the high resolution portion of its field of view to a delimited area, a displayed image for which is observed directly upon the console display screen by the operator. In order to accompolish this task, such systems employ, as part of the command console, an oculometer which observes where the eye of the operator is looking on the display screen. The oculometer generates signals that are transmitted to the remote vehicle to operate a camera servo mechanism so as to point the high resolution imaging optics to that location on the scene being simultaneously viewed by the camera equipment and the console operator.
Exemplary patent literature which describes such systems includes the U.S. patent to Holmes U.S. Pat. No. 3,507,988 and the U.S. patent to Lewis U.S. Pat. No. 4,028,725. The systems described in these patents employ an operator viewing position sensor which generates output signals indicating the point of observation on a display screen of the operator. The output signals are used to control high resolution viewing optics so as to maintain the high resolution image of the scene at the location where the observer is looking.
In the system described in the Holmes patent, an eye position sensor monitors the movement of the observer's eye and causes a high resolution spiral scan pattern of a camera tube to be centered about the observer's instantaneous line of sight. Simultaneously, a display tube located at the observer's console, which receives video information corresponding to the high resolution scan from the remote camera, will recreate such information at that point on the display tube being observed by the operator.
Similarly, in the system described in the Lewis patent the output of an oculometer system, which monitors helmet position and eye angle position, drives respective servo mechanisms in the remote vehicle and at the display terminal. The remote vehicle includes a narrow field of view sensor whose optical axis is made to coincide with the axis of observation of the control console operator as he views the display image. The system also includes a lower resolution wide field of view sensor, image data for which is transmitted from the remote vehicle to the control console and is combined with the high resolution information to provide background adjacent the high resolution portion of the scene to which the operator's view is directed.
Basically, each of the systems described in these patents includes a high resolution imaging system and a low resolution imaging system mounted within the remotely piloted vehicle. The oculometer output signals are caused to operate a camera servo mechanism which effectively maintains the high resolution portion of the scanning optics directed at that portion of the scene to which the eyes of the observer are directed (i.e. the operator's instantaneous look angle). With these types of systems, the camera in the remotely piloted vehicle must be continuously coupled to the data link between the remote vehicle and the observer's console. Moreover, it is the operation of the camera equipment, including slewing of the same in a remotely piloted vehicle, that is made to respond to the look angle of the console operator.